1. Field of the Invention
The present invention relates to the field of display, and in particular to a quantum dot (QD) polarizer and manufacturing method thereof.
2. The Related Arts
To meet the demands on the display for wide spectrum and color saturation, an effective option for major display manufacturers is to add photoluminescence quantum dots (QD) in the backlight structure.
In use of QD as a nano-scale material, the quantum confinement effect is obvious because of the narrow size (<10 nano). When excited by light, and the excitation energy level exceeds the band gap, the electrons leap from valence band to conduction band, and emitted in an optical energy to form different colors. Also, by controlling the size of QD, different colors can be adjusted. Using the blue light from the light emitting diode (LED) is able to effectively increase the color spectrum of the display.
The known mainstream QD backlight technologies are divided into two approaches: one is to package the QD into a glass tube and placed in front of the backlight; and the other is to manufacture the QD into a thin film for insertion between the backlight module and the display panel. Understandably, these technologies require specific facility for manufacturing QD, and thus increase cost.
As shown in FIG. 1, a common polarizer has a layered structure, from top down, comprising: a surface protective film 110, a first protective layer 120, a polarization layer 130, a second protective layer 140, an adhesive layer 150, and a peel-off protective film 160, wherein when attaching the polarizer, the peel-off film 160 is peeled off to expose the adhesive layer 150. After the polarizer is attached, the surface protective film 110 will be peeled off. The core of the structure of the polarizer is the polarization layer 130, which usually comprises a polyvinyl alcohol (PVA) layer with iodine molecules able to polarize; and the first protective layer 120 and the second protective layer 140 are transparent cellulose triacetate (TAC) layer, mainly to maintain the polarization molecules in the polarization layer 130 to stay extended to avoid dehydration and to protect from external influence.
Therefore, the layered structure of the polarizer is suitable for adding QD film, such as, China Patent CN102854558 and Korea Patent KR20070107498A, disclosed methods for adding a QD layer, i.e., a quantum bar layer with polarization effect between the protective layer and the polarization layer. However, these methods require additional QD layer process, which leads to degraded transmittance, higher cost and thicker display devices.